1 /* 2 * fixed.c 3 * 4 * Copyright 2008 Wolfson Microelectronics PLC. 5 * 6 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com> 7 * 8 * Copyright (c) 2009 Nokia Corporation 9 * Roger Quadros <ext-roger.quadros@nokia.com> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License as 13 * published by the Free Software Foundation; either version 2 of the 14 * License, or (at your option) any later version. 15 * 16 * This is useful for systems with mixed controllable and 17 * non-controllable regulators, as well as for allowing testing on 18 * systems with no controllable regulators. 19 */ 20 21 #include <linux/err.h> 22 #include <linux/mutex.h> 23 #include <linux/module.h> 24 #include <linux/platform_device.h> 25 #include <linux/regulator/driver.h> 26 #include <linux/regulator/fixed.h> 27 #include <linux/gpio.h> 28 #include <linux/slab.h> 29 #include <linux/of.h> 30 #include <linux/of_gpio.h> 31 #include <linux/regulator/of_regulator.h> 32 #include <linux/regulator/machine.h> 33 34 struct fixed_voltage_data { 35 struct regulator_desc desc; 36 struct regulator_dev *dev; 37 }; 38 39 40 /** 41 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info 42 * @dev: device requesting for fixed_voltage_config 43 * 44 * Populates fixed_voltage_config structure by extracting data from device 45 * tree node, returns a pointer to the populated structure of NULL if memory 46 * alloc fails. 47 */ 48 static struct fixed_voltage_config * 49 of_get_fixed_voltage_config(struct device *dev) 50 { 51 struct fixed_voltage_config *config; 52 struct device_node *np = dev->of_node; 53 const __be32 *delay; 54 struct regulator_init_data *init_data; 55 56 config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config), 57 GFP_KERNEL); 58 if (!config) 59 return ERR_PTR(-ENOMEM); 60 61 config->init_data = of_get_regulator_init_data(dev, dev->of_node); 62 if (!config->init_data) 63 return ERR_PTR(-EINVAL); 64 65 init_data = config->init_data; 66 init_data->constraints.apply_uV = 0; 67 68 config->supply_name = init_data->constraints.name; 69 if (init_data->constraints.min_uV == init_data->constraints.max_uV) { 70 config->microvolts = init_data->constraints.min_uV; 71 } else { 72 dev_err(dev, 73 "Fixed regulator specified with variable voltages\n"); 74 return ERR_PTR(-EINVAL); 75 } 76 77 if (init_data->constraints.boot_on) 78 config->enabled_at_boot = true; 79 80 config->gpio = of_get_named_gpio(np, "gpio", 0); 81 /* 82 * of_get_named_gpio() currently returns ENODEV rather than 83 * EPROBE_DEFER. This code attempts to be compatible with both 84 * for now; the ENODEV check can be removed once the API is fixed. 85 * of_get_named_gpio() doesn't differentiate between a missing 86 * property (which would be fine here, since the GPIO is optional) 87 * and some other error. Patches have been posted for both issues. 88 * Once they are check in, we should replace this with: 89 * if (config->gpio < 0 && config->gpio != -ENOENT) 90 */ 91 if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER)) 92 return ERR_PTR(-EPROBE_DEFER); 93 94 delay = of_get_property(np, "startup-delay-us", NULL); 95 if (delay) 96 config->startup_delay = be32_to_cpu(*delay); 97 98 if (of_find_property(np, "enable-active-high", NULL)) 99 config->enable_high = true; 100 101 if (of_find_property(np, "gpio-open-drain", NULL)) 102 config->gpio_is_open_drain = true; 103 104 if (of_find_property(np, "vin-supply", NULL)) 105 config->input_supply = "vin"; 106 107 return config; 108 } 109 110 static struct regulator_ops fixed_voltage_ops = { 111 }; 112 113 static int reg_fixed_voltage_probe(struct platform_device *pdev) 114 { 115 struct fixed_voltage_config *config; 116 struct fixed_voltage_data *drvdata; 117 struct regulator_config cfg = { }; 118 int ret; 119 120 if (pdev->dev.of_node) { 121 config = of_get_fixed_voltage_config(&pdev->dev); 122 if (IS_ERR(config)) 123 return PTR_ERR(config); 124 } else { 125 config = dev_get_platdata(&pdev->dev); 126 } 127 128 if (!config) 129 return -ENOMEM; 130 131 drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data), 132 GFP_KERNEL); 133 if (drvdata == NULL) { 134 dev_err(&pdev->dev, "Failed to allocate device data\n"); 135 ret = -ENOMEM; 136 goto err; 137 } 138 139 drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL); 140 if (drvdata->desc.name == NULL) { 141 dev_err(&pdev->dev, "Failed to allocate supply name\n"); 142 ret = -ENOMEM; 143 goto err; 144 } 145 drvdata->desc.type = REGULATOR_VOLTAGE; 146 drvdata->desc.owner = THIS_MODULE; 147 drvdata->desc.ops = &fixed_voltage_ops; 148 149 drvdata->desc.enable_time = config->startup_delay; 150 151 if (config->input_supply) { 152 drvdata->desc.supply_name = kstrdup(config->input_supply, 153 GFP_KERNEL); 154 if (!drvdata->desc.supply_name) { 155 dev_err(&pdev->dev, 156 "Failed to allocate input supply\n"); 157 ret = -ENOMEM; 158 goto err_name; 159 } 160 } 161 162 if (config->microvolts) 163 drvdata->desc.n_voltages = 1; 164 165 drvdata->desc.fixed_uV = config->microvolts; 166 167 if (config->gpio >= 0) 168 cfg.ena_gpio = config->gpio; 169 cfg.ena_gpio_invert = !config->enable_high; 170 if (config->enabled_at_boot) { 171 if (config->enable_high) 172 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 173 else 174 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 175 } else { 176 if (config->enable_high) 177 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW; 178 else 179 cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH; 180 } 181 if (config->gpio_is_open_drain) 182 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN; 183 184 cfg.dev = &pdev->dev; 185 cfg.init_data = config->init_data; 186 cfg.driver_data = drvdata; 187 cfg.of_node = pdev->dev.of_node; 188 189 drvdata->dev = regulator_register(&drvdata->desc, &cfg); 190 if (IS_ERR(drvdata->dev)) { 191 ret = PTR_ERR(drvdata->dev); 192 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret); 193 goto err_input; 194 } 195 196 platform_set_drvdata(pdev, drvdata); 197 198 dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name, 199 drvdata->desc.fixed_uV); 200 201 return 0; 202 203 err_input: 204 kfree(drvdata->desc.supply_name); 205 err_name: 206 kfree(drvdata->desc.name); 207 err: 208 return ret; 209 } 210 211 static int reg_fixed_voltage_remove(struct platform_device *pdev) 212 { 213 struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev); 214 215 regulator_unregister(drvdata->dev); 216 kfree(drvdata->desc.supply_name); 217 kfree(drvdata->desc.name); 218 219 return 0; 220 } 221 222 #if defined(CONFIG_OF) 223 static const struct of_device_id fixed_of_match[] = { 224 { .compatible = "regulator-fixed", }, 225 {}, 226 }; 227 MODULE_DEVICE_TABLE(of, fixed_of_match); 228 #endif 229 230 static struct platform_driver regulator_fixed_voltage_driver = { 231 .probe = reg_fixed_voltage_probe, 232 .remove = reg_fixed_voltage_remove, 233 .driver = { 234 .name = "reg-fixed-voltage", 235 .owner = THIS_MODULE, 236 .of_match_table = of_match_ptr(fixed_of_match), 237 }, 238 }; 239 240 static int __init regulator_fixed_voltage_init(void) 241 { 242 return platform_driver_register(®ulator_fixed_voltage_driver); 243 } 244 subsys_initcall(regulator_fixed_voltage_init); 245 246 static void __exit regulator_fixed_voltage_exit(void) 247 { 248 platform_driver_unregister(®ulator_fixed_voltage_driver); 249 } 250 module_exit(regulator_fixed_voltage_exit); 251 252 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>"); 253 MODULE_DESCRIPTION("Fixed voltage regulator"); 254 MODULE_LICENSE("GPL"); 255 MODULE_ALIAS("platform:reg-fixed-voltage"); 256